The present invention relates to a control mechanism for providing differential opening of the throttle valve which controls the amount of air introduced into the induction manifold of an internal combustion engine, particularly one having fuel injection. Such a device is of particular value for use in connection with engines which are to be fitted to automobiles, whereby to provide differential control of the air drawn in for mixing with the fuel.
It is known that the variation of the fuel/air mixture from a fuel rich to a lean ratio is important in reducing the atmospheric pollution caused by an internal combustion engine, for which there exist specific international rules, which lay down specific values of the parameters to which internal combustion engines must now conform. These values vary in individual countries.